抄録
In recent years, amount of urban waste is increasing and a shortage of land disposal site has been caused as a serious problem. The study was carried out to establish recycling process of fly ash included with chloride without generating any secondary waste. The following summarized the results.
Chloride in the fly ash was leached with water. We can downsize facilities for subsequent process, because volume of residue was reduced by 1/5 to 1/10.
Copper and zinc ions in the residue were leached with sulfuric acid solution. From this filtrate, copper metal was recovered by cementation and zinc hydroxide was recovered by adjustment pH, respectively.
Lead ion was leached with aqueous solution of sodium hydroxide and was recovered as lead sulfide. At the same time, calcium sulfate was converted to calcium hydroxide which was able to be utilized as a raw material for cement.
The waste water caused from this process could be content with effluent standard by water treatment attaching importance to de-selenium processing.
